Exercise machines often have user supports which support a user in an exercise position during an exercise. Some machines have stationary user supports, while others have user supports which move during an exercise. Abdominal exercise machines are known which have a seat supported on a frame and an arm and head support which is mounted for rotary movement relative to the seat and which can be pulled down by the user in order to simulate an abdominal crunch exercise. One example is U.S. Pat. No. 6,186,926 of Ellis. The seat is fixed in position in this machine. In some abdominal exercise machines, the seat rotates up as the arm and head support rotates down towards the seat. Moving user supports or seats which are angled to one side can be awkward to sit on or get off, and can also make it difficult for the exerciser to position their body properly in order to perform an exercise. Other exercise machines are known in which all or part of a user support travels during an exercise, but these are typically not particularly versatile and only allow for exercise of one type of muscle or muscle group.